Unless otherwise indicated herein, the approaches described in this section are not prior art to the claims in this application and are not admitted to be prior art by inclusion in this section.
The amount of electric charge that a battery can store is typically referred to as the battery's “capacity”. The state of charge (SoC) of a battery expresses the battery's present capacity as a percentage of the battery's maximum capacity. The SoC of a battery is dependent on inherent chemical characteristics of the battery and characteristics of the electrical system in which the battery is installed, as well as operating conditions of the battery. Batteries that use a specific battery technology and chemistry will behave differently from batteries that use a different battery technology and chemistry. Furthermore, even batteries that use the same technology and chemistry may vary from manufacturer to manufacturer, and from build-lot to build-lot by the same manufacturer.
The performance of individual batteries will also vary based on operating conditions such as temperature, age of the battery, the load coupled to the battery, and so on. The variety and complexity of factors that can affect the performance of a battery are further complicated by the various non-linear relationships between the factors. As a result, estimating the SoC of a battery can be highly sensitive to the specific conditions in which the battery is used or operated due to the complex interplay of measurable variables. Accordingly, conventional systems, methods, and apparatus for determining battery SoC are more computational and memory intensive than is desirable in contemporary mobile electronic devices.